In a short hallway, somewhere inside the labyrinthine Basel HQ of Herzog & de Meuron, stands a small Chinese wooden table, shaped so that two of its legs rest on the floor and two on the wall. It’s an artwork by Ai Weiwei, a friend of the Swiss architects and a regular collaborator. Above it hangs a giant light fitting, designed for their most famous collaboration: Beijing’s Bird’s Nest Olympic stadium. This “shrine to Weiwei”, as the architects put it, says plenty about their practice: few architects have cultivated such close ties to artists and the art world in general, or benefited from them so handsomely.

In room after room of their vast studio, members of their 350-strong team labour on new art galleries and cultural buildings. Here’s one for Miami: an open concrete structure with an oversailing roof. Over there is a huge art gallery in Kolkata; elsewhere, there are buildings in New York, Hong Kong and São Paolo. Meanwhile, on an island in Hamburg, their stunning Elbphilharmonie concert hall has just had its topping-out ceremony.

And this summer the architects will be revisiting London, home of their Tate Modern. In July, we’ll see the first signs of their long-delayed extension to the gallery: a conversion of the old power station’s subterranean oil tanks. But before that, they’ll unveil the 12th in the Serpentine Gallery’s series of temporary summer pavilions, another collaboration with Ai.

ust as Basel is an art hub, so too is it home to pharmaceutical giants, who have regularly employed their local super-duo. In fact, the whole city is strewn with the architects’ early works, from industrial buildings to high-rise office towers to the local football stadium (plus, of course, galleries and museums). Not that you’d instantly recognise their work: what’s facilitated Herzog and De Meuron’s ascent has been their capacity to re-think architecture anew. Their nearby Central Signal Box, from 1999, wrapped a bog-standard piece of railway infrastructure in twisting bands of copper to create a sculptural landmark.